terminfo: basic Source structure and can encode

src/main.zig

@@ -190,6 +190,7 @@ test {
     // Libraries
     _ = @import("segmented_pool.zig");
     _ = @import("terminal/main.zig");
+    _ = @import("terminfo/main.zig");
 
     // TODO
     _ = @import("blocking_queue.zig");

src/terminfo/Source.zig

@@ -0,0 +1,98 @@
+//! Terminfo source format. This can be used to encode terminfo files.
+//! This cannot parse terminfo source files yet because it isn't something
+//! I need to do but this can be added later.
+//!
+//! Background: https://invisible-island.net/ncurses/man/terminfo.5.html
+
+const Source = @This();
+
+const std = @import("std");
+
+/// The set of names for the terminal. These match the TERM environment variable
+/// and are used to look up this terminal. Historically, the final name in the
+/// list was the most common name for the terminal and contains spaces and
+/// other characters. See terminfo(5) for details.
+names: []const []const u8,
+
+/// The set of capabilities in this terminfo file.
+capabilities: []const Capability,
+
+/// A capability in a terminfo file. This also includes any "use" capabilities
+/// since they behave just like other capabilities as documented in terminfo(5).
+pub const Capability = struct {
+    /// The name of capability. This is the "Cap-name" value in terminfo(5).
+    name: []const u8,
+    value: Value,
+
+    pub const Value = union(enum) {
+        /// Canceled value, i.e. suffixed with @
+        canceled: void,
+
+        /// Boolean values are always true if they exist so there is no value.
+        boolean: void,
+
+        /// Numeric values are always "unsigned decimal integers". The size
+        /// of the integer is unspecified in terminfo(5). I chose 32-bits
+        /// because it is a common integer size but this may be wrong.
+        numeric: u32,
+
+        string: []const u8,
+    };
+};
+
+/// Encode as a terminfo source file. The encoding is always done in a
+/// human-readable format with whitespace. Fields are always written in the
+/// order of the slices on this struct; this will not do any reordering.
+pub fn encode(self: Source, writer: anytype) !void {
+    // Encode the names in the order specified
+    for (self.names, 0..) |name, i| {
+        if (i != 0) try writer.writeAll("|");
+        try writer.writeAll(name);
+    }
+    try writer.writeAll(",\n");
+
+    // Encode each of the capabilities in the order specified
+    for (self.capabilities) |cap| {
+        try writer.writeAll("\t");
+        try writer.writeAll(cap.name);
+        switch (cap.value) {
+            .canceled => try writer.writeAll("@"),
+            .boolean => {},
+            .numeric => |v| try writer.print("#{d}", .{v}),
+            .string => |v| try writer.print("={s}", .{v}),
+        }
+        try writer.writeAll(",\n");
+    }
+}
+
+test "encode" {
+    const src: Source = .{
+        .names = &.{
+            "ghostty",
+            "xterm-ghostty",
+            "Ghostty",
+        },
+
+        .capabilities = &.{
+            .{ .name = "am", .value = .{ .boolean = {} } },
+            .{ .name = "ccc", .value = .{ .canceled = {} } },
+            .{ .name = "colors", .value = .{ .numeric = 256 } },
+            .{ .name = "bel", .value = .{ .string = "^G" } },
+        },
+    };
+
+    // Encode
+    var buf: [1024]u8 = undefined;
+    var buf_stream = std.io.fixedBufferStream(&buf);
+    try src.encode(buf_stream.writer());
+
+    const expected =
+        \\ghostty|xterm-ghostty|Ghostty,
+        \\	am,
+        \\	ccc@,
+        \\	colors#256,
+        \\	bel=^G,
+        \\
+    ;
+    try std.testing.expectEqualStrings(@as([]const u8, expected), buf_stream.getWritten());
+}

src/terminfo/main.zig

@@ -0,0 +1,12 @@
+//! Package terminfo provides functionality related to terminfo/termcap files.
+//!
+//! At the time of writing this comment, the focus is on generating terminfo
+//! files so that we can maintain our terminfo in Zig instead of hand-writing
+//! the archaic (imo) terminfo format by hand. But eventually we may want to
+//! extract this into a more full-featured library on its own.
+
+pub const Source = @import("Source.zig");
+
+test {
+    @import("std").testing.refAllDecls(@This());
+}